Error using TypeService getType() method

Hey, I am using the TypeService interface and calling the getType() method to return Appian DataType value for a CDT passed into a smart service.

cdt variable is of class TypedValue

Long cdtTypeId= cdt.getInstanceType();
Datatype cdtType= ts.getType(cdtTypeId);

But I get this error.. The type com.appiancorp.cache.CoupledValue cannot be resolved. It is indirectly referenced from required .class files

This shows up in in the IDE during build for the line ts.getType(cdtTypeId).

Does anyone know what is needed to get this to work. Or another way to get Datatype from the TypedValue class